Evolution of placentotrophy: Using viviparous sharks as a model to understand vertebrate placental evolution

Alice L. Buddle, James U. Van Dyke, Michael B. Thompson, Colin A. Simpfendorfer, Camilla M. Whittington

Research output: Contribution to journalSpecial issuepeer-review

8 Citations (Scopus)

Abstract

Reproducing sharks must provide their offspring with an adequate supply of nutrients to complete embryonic development. In oviparous (egg-laying) sharks, offspring develop outside the mother, and all the nutrients required for embryonic growth are contained in the egg yolk. Conversely, in viviparous (live-bearing) sharks, embryonic development is completed inside the mother, providing offspring with the opportunity to receive supplementary embryonic nourishment, known as matrotrophy. Viviparous sharks exhibit nearly all forms of matrotrophy known in vertebrates, including a yolk-sac placenta, which involves several significant ontogenetic modifications to fetal and maternal tissues. The selective pressures that have driven the evolution of complex placentas in some shark species, but not in others, are unresolved. Herein we review the mechanisms of reproductive allocation and placental diversity in sharks, and consider the application of both adaptive and conflict hypotheses for the evolution of placental nutrient provisioning. Both have likely played roles in placental evolution in sharks, perhaps at different times in evolutionary history. Finally, we recommend sharks as an outstanding model system to investigate the evolution of placentas and mechanisms for fetal nutrition during pregnancy in vertebrates.
Original languageEnglish
Pages (from-to)908-924
Number of pages17
JournalMarine and Freshwater Research
Volume70
Issue number7
Early online date20 Sep 2018
DOIs
Publication statusPublished - 2019

Fingerprint

Dive into the research topics of 'Evolution of placentotrophy: Using viviparous sharks as a model to understand vertebrate placental evolution'. Together they form a unique fingerprint.

Cite this